Impeller, blower, and vacuum cleaner

ABSTRACT

An impeller is rotatable about a vertically extending central axis and includes a base portion extending radially outward as it extends downward, first blades circumferentially arrayed on the upper surface of the base portion and extending on one side in the circumferential direction as it extends upward, and second blades between the circumferential direction of the circumferentially adjacent first blades and extending on one side in the circumferential direction as it extends upward. The radial outer end of the second blade is on one side in the circumferential direction relative to the middle in the circumferential direction of the radial outer end of the circumferentially adjacent first blade.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority under 35 U.S.C. § 119 to United States of American Application No. 62/856,274 filed on Jun. 3, 2019 and Japanese Application No. 2020-079489 filed on Apr. 28, 2020, the entire contents of which are hereby incorporated herein by reference.

1. FIELD OF THE INVENTION

The present disclosure relates to an impeller, a blower, and a vacuum cleaner.

2. BACKGROUND

As a conventional impeller, one that is provided in an electric blower is known, in which the impeller specific speed Ns (min−1, m³/min, m reference)=rotational speed N×√(flow rate Q)÷pump head H ¾=less than 1200, and the inlet area of the impeller is larger than the outlet area of the impeller.

In the conventional impeller, the above configuration allows efficiency to be improved by converting the kinetic energy of the fluid into static pressure at the outlet of the impeller. However, the conventional impeller is required to further improve the blowing efficiency.

SUMMARY

An impeller according to an example embodiment of the present disclosure is rotatable about a vertically extending central axis. The impeller includes a base portion extending radially outward as it extends downward, a plurality of first blades circumferentially arrayed on the upper surface of the base portion and extending on one side in the circumferential direction as it extends upward, and a plurality of second blades between the circumferential direction of the circumferentially adjacent first blades and extending on one side in the circumferential direction as it extends upward. The radial outer end of the second blade is on one side in the circumferential direction relative to the middle in the circumferential direction of the radial outer end of the circumferentially adjacent first blade.

The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a vacuum cleaner according to an example embodiment of the present disclosure.

FIG. 2 is a perspective view of a blower according to an example embodiment of the present disclosure.

FIG. 3 is a longitudinal cross-sectional view of the blower according to an example embodiment of the present disclosure.

FIG. 4 is a perspective view of an impeller according to an example embodiment of the present disclosure.

FIG. 5 is a front view of the impeller according to an example embodiment of the present disclosure.

FIG. 6 is a plan view of the impeller according to an example embodiment of the present disclosure.

FIG. 7 is a longitudinal cross-sectional view of the impeller according to an example embodiment of the present disclosure.

FIG. 8 is a perspective view of the impeller according to an example embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, example embodiments of the present disclosure will be described with reference to the drawings. It is to be noted that in this description, the direction in which a central axis J of a blower B extends is referred to as “vertical” or “axial”, the direction orthogonal to the central axis J of the blower B is referred to as “radial”, and the direction along an arc centered on the central axis J of the blower B is referred to as “circumferential”. However, the above-mentioned “vertical” does not limit the direction of the blower B when it is actually incorporated into an apparatus. Furthermore, in the drawings, for the sake of convenience, the contents of the drawings such as dimensions may be different from the actual structure. In addition, in the drawings, hatching may be omitted for the sake of convenience. It is to be noted that in this description, the words such as vertical, axial, radial, and circumferential do not strictly indicate only these directions but also include directions slightly inclined from these directions.

In addition, in the present description, the shape and positional relationship of each part of a vacuum cleaner A will be described with the direction of approaching a floor surface F being “downward” and the direction of departing from the floor surface F being “upward”. It is to be noted that these directions are names used merely for explanation, and do not limit the actual positional relationships and directions.

The vacuum cleaner A according to an example embodiment of the present disclosure will be described. FIG. 1 is a perspective view of the vacuum cleaner A according to an example embodiment of the present disclosure. The vacuum cleaner A is a so-called stick type electric vacuum cleaner, and includes a chassis 102 having an intake portion 103 and an exhaust portion 104 formed on a lower surface and an upper surface, respectively. A power cord (not shown) is led out from the rear surface of the chassis 102. The power cord is connected to a power outlet (not shown) provided on the side wall surface of the living room, and supplies power to the vacuum cleaner A. It is to be noted that the vacuum cleaner A may be a so-called robot type, canister type, or handy type vacuum cleaner.

An air passage (not shown) connecting the intake portion 103 and the exhaust portion 104 is formed in the chassis 102. A dust collecting portion (not shown), a filter (not shown), and the blower B are arranged in order from the upstream side toward the downstream side in the air passage. The blower B has an impeller 2 described later. Dust contained in gas flowing in the air passage is captured by the filter and collected in a dust collecting portion formed in a container shape. The dust collecting portion and the filter are configured removably to the chassis 102.

A grip portion 105 and an operation portion 106 are provided on the upper portion of the chassis 102. The user can move the vacuum cleaner A by gripping the grip portion 105. The operation portion 106 has a plurality of buttons 106 a, and performs operation setting of the vacuum cleaner A by the operation of the buttons 106 a. For example, the operation of the buttons 106 a gives the blower B instructions of starting driving, stopping driving, and changing the number of rotations. The downstream end (upper end of the figure) of a rod-shaped suction pipe 107 is connected to the intake portion 103. A suction nozzle 108 is removably attached to the suction pipe 107 at the upstream end of the suction pipe 107. Dust on the floor surface F is sucked into the suction pipe 107 through the suction nozzle 108. The vacuum cleaner A has the blower B described later. This can improve the blowing efficiency of the blower B mounted on the vacuum cleaner A.

FIG. 2 is a perspective view of the blower B according to an example embodiment of the present disclosure, and FIG. 3 is a longitudinal cross-sectional view of the blower B according to an example embodiment of the present disclosure. FIG. 3 is a longitudinal cross-sectional view of an imaginary cross section A-A in FIG. 2.

As shown in FIGS. 2 and 3, the blower B has a motor 1, the impeller 2, and a housing 3. The motor 1 is a so-called inner rotor type motor.

The motor 1 has a stator 11, a rotor 12, a motor housing 13, a bearing 14, and a substrate 15. The rotor 12 is rotatable about the vertically extending central axis J and radially faces the stator 11. The motor housing 13 surrounds at least a part of the stator 11 and the rotor 12.

The stator 11 has a stator core 111, an insulator 112, and a coil 113. The stator core 111 is made of a magnetic material and has an annular core back and a teeth portion extending radially inward from the core back. At least a part of the teeth portion is surrounded by the insulator 112. The coil 113 is formed by winding a conductive wire around the teeth portion via the insulator 112.

The rotor 12 has a shaft 121, a magnet 122, an upper spacer 123, and a lower spacer 124. The shaft 121 is arranged along the central axis J. The magnet 122 is fixed to the shaft 121 and radially faces the radial inner end of portion the teeth portion. The upper spacer 123 and the lower spacer 124 are fixed to the shaft 121, respectively. The upper surface of the magnet 122 is in contact with the lower surface of the upper spacer 123, and the lower surface of the magnet 122 is in contact with the upper surface of the lower spacer 124. The magnet 122 is fixed by being axially sandwiched by the upper spacer 123 and the lower spacer 124.

The motor housing 13 has an upper motor housing 131, a lower motor housing 132, and a fixing member 133. The lower motor housing 132 is arranged downward relative to the upper motor housing 131. The upper motor housing 131 and the lower motor housing 132 surround at least a part of the stator 11 and the rotor 12, respectively. The stator core 111, the upper motor housing 131, and the lower motor housing 132 are fixed by the fixing member 133. In the present embodiment, the fixing member 133 is a screw.

The bearing 14 includes an upper bearing 141 and a lower bearing 142. The upper bearing 141 and the lower bearing 142 are fixed to the upper motor housing 131 and the lower motor housing 132, respectively, and rotatably support the shaft 121 around the central axis J.

The substrate 15 is arranged downward relative to the stator core 111. An electronic component 151 is arranged on the upper surface of the substrate 15. The electronic component 151 is, for example, a capacitor, an FET, or the like. The substrate 15 is fixed to the lower motor housing 132 by a fixing member 152.

The impeller 2 has a base portion 21, a first blade 22, and a second blade 23. The impeller 2 is fixed to the shaft 121. A downward extending cylindrical hub 211 is arranged on the lower surface of the base portion 21. The hub 211 is provided with an upwardly recessed recess portion, and the upper end portion of the shaft 121 is fixed in a state of being inserted into the recess portion. Thus, the impeller 2 is rotatable about the central axis J integrally with the shaft 121. That is, the impeller 2 is rotatable about the vertically extending central axis J.

The housing 3 has an impeller cover 31, an outer housing 32, and an inner housing 33. The impeller cover 31 surrounds at least a part of the impeller 2 upward and radially outward. The center of the impeller cover 31 is provided with an axially opening intake port 311. The impeller cover 31 has a curved surface portion 312 extending radially outward as it extends downward, and a cylindrical portion 313 extending downward from the radial outer edge of the curved surface portion.

The outer housing 32 is an axially extending cylindrical portion. The upper end portion of the outer housing 32 is fixed to the cylindrical portion 313. The lower end portion of the outer housing 32 is fixed to the lower motor housing 132. The inner housing 33 is arranged radially inward of the outer housing 32. The inner housing 33 has a top plate portion 331 arranged downward of the base portion 21 and stretching in a direction intersecting with the central axis J, and a cylindrical portion 332 extending downward from the radial outer edge of the top plate portion. A flow path is formed in the radial direction between a radial inner surface of the outer housing 32 and a radial outer surface of the cylindrical portion 332.

The gas sucked into the impeller cover 31 from the intake port 311 is discharged downward and radially outward by the impeller 2, flows downward in the flow path between the outer housing 32 and the cylindrical portion 332, flows along the radial inner surface of the lower motor housing 132, and is then discharged to the external space of the blower B. The blower B has the impeller 2. This improves the blowing efficiency of the blower B.

FIG. 4 is a perspective view of the impeller 2 according to an example embodiment of the present disclosure, FIG. 5 is a front view of the impeller 2 according to an example embodiment of the present disclosure, FIG. 6 is a plan view of the impeller 2 according to an example embodiment of the present disclosure, FIG. 7 is a longitudinal cross-sectional view of then impeller 2 according to an example embodiment of the present disclosure, and FIG. 8 is a perspective view of the impeller 2 according to an example embodiment of the present disclosure. FIGS. 4 and 8 are a perspective view of the impeller 2 viewed from the upward and a perspective view of the impeller 2 viewed from the downward, respectively. FIG. 7 is a longitudinal cross-sectional view of the impeller in a case of being cut by an imaginary cross section B-B in FIG. 6.

Hereinafter, the structure of the impeller 2 will be described in detail with reference to FIGS. 4 to 8. The impeller 2 is a so-called mixed flow type three-dimensional impeller. The impeller 2 is rotatable about the vertically extending central axis J. The impeller 2 has the base portion 21, the plurality of first blades 22, and the plurality of second blades 23. The first blade 22 is a so-called main blade, and the second blade 23 is a so-called auxiliary blade. The base portion 21 stretches radially outward as it extends downward. As shown in FIGS. 7 and 8, the downward extending cylindrical hub 211 is formed in the central portion of the lower surface of the base portion 21. The axial thickness of the base portion 21 is substantially constant radially outward relative to the hub 211. Therefore, an upwardly recessed recess portion 212 is formed downward of the base portion 21 radially outward relative to the hub 211.

As shown in FIGS. 4 to 8, the plurality of first blades 22 are circumferentially arrayed on the upper surface of the base portion 21. The plurality of first blades 22 extend on one side in a circumferential direction C as it extends upward. Here, the one side in the circumferential direction C is the forward in the rotation direction of the impeller 2, and the other side in the circumferential direction C is the backward in the rotation direction of the impeller 2. A radial inner edge 221 of the first blade 22 extends upward as it extends radially outward. This enlarges the area of the first blade 22, thereby improving the blowing efficiency. That is, the blowing efficiency is improved because the area of the pressure surface of the first blade 22 becomes larger as compared with a case where the radial inner edge 221 extends radially outward along a plane orthogonal to the central axis J, for example. As shown in FIG. 5, the radial inner edge 221 extends in the normal direction on the upper surface of the base portion 21.

As shown in FIG. 6, in planar view, the radial inner edge 221 of the first blade 22 is arranged along an imaginary line L radiating from the central axis J. That is, the radial inner edge 221 extends radially. This can enlarge the area of a space formed in between the circumferential direction C of the radial inner edges 221 of the adjacent first blades 22, thereby improving the blowing efficiency. In the impeller 2 having the above-described characteristics, the area of the space formed in between the circumferential direction C of the radial inner edges 221 adjacent in the circumferential direction C can be enlarged as compared with a case where the radial inner edge is curved on one side in the circumferential direction C as it extends radially outward in planar view, for example.

A radial outer edge 223 of the first blade 22 extends upward as it extends radially outward. This enlarges the area of the first blade 22, thereby improving the blowing efficiency. That is, the blowing efficiency is improved because the area of the pressure surface of the first blade 22 becomes larger as compared with a case where the radial outer edge extends upward along a direction parallel to the central axis J, for example. As shown in FIG. 5, the radial outer edge 223 extends in the normal direction on the upper surface of the base portion 21.

As shown in FIGS. 4 and 5, the upper edge of the first blade does not have a constant radius of curvature, but the radius of curvature differs depending on an upper edge 226 portion of the first blade 22. More specifically, when the first blade 22 is viewed from the radial outward, the upper portion of the upper edge 226 of the first blade 22 is a curved surface protruding to the other side in the circumferential direction C, and the lower portion of the upper edge 226 of the first blade 22 is a curved surface protruding to one side in the circumferential direction C. That is, when the first blade 22 is viewed from the radial outward, the upper portion of the upper edge 226 is curved so as to expand to the other side in the circumferential direction C, and the lower portion of the upper edge 226 is curved so as to expand to one side in the circumferential direction C. This allows gas to be sucked along the curved surface protruding to the other side in the circumferential direction C in the upper portion of the first blade 22, and the suction efficiency to be improved. Furthermore, it is possible to discharge gas radially outward and downward along the curved surface protruding to one side in the circumferential direction C in the lower portion of the first blade 22, thereby improving the blowing efficiency.

The plurality of second blades 23 are arranged in between the circumferential direction of the first blades 22 adjacent in the circumferential direction C. The plurality of second blades 23 extend on one side in a circumferential direction C as it extends upward. A radial inner edge 231 of the second blade 23 extends upward as it extends radially outward. This enlarges the area of the second blade 23, thereby improving the blowing efficiency. That is, the blowing efficiency is improved because the area of the pressure surface of the second blade 23 becomes larger than that in a case where the radial inner edge 231 extends radially outward along a plane orthogonal to the central axis J, for example.

In planar view, the radial inner edge 231 of the second blade 23 is arranged on one side in the circumferential direction C as it extends radially outward. In the present embodiment, the radial inner edge 231 is a line-segment-shaped portion extending in a direction inclined to one side of the circumferential direction C relative to the normal direction of the base portion 21. This results in an increase in the area of the second blade 23, thereby improving the blowing efficiency. That is, the blowing efficiency is improved because the area of the pressure surface of the second blade 23 becomes larger than that in a case where the radial inner edge 231 extends in the normal direction of the base portion 21, for example.

In planar view, a radial outer end 237 at the radial inner edge 231 of at least one of the second blades 23 is arranged on the imaginary line L. More specifically, the radial outer end 237 at the radial inner edge 231 of the second blade 23 adjacent to one side in the circumferential direction C of a certain first blade 22 is arranged on the imaginary line L connecting the central axis J and the radial inner edge 221 of the first blade 22. Due to this, the radial outer end 237 of the radial inner edge 231 is arranged on the imaginary line L that overlaps the radial inner edge 221 of the first blade 22, and hence gas smoothly flows on both the pressure surface side and the negative pressure side of the second blade 23, thereby improving the blowing efficiency. It is to be noted that in the present embodiment, the radial outer end 237 at the radial inner edge 231 of the second blade 23 adjacent to one side in the circumferential direction C of all the first blades 22 is arranged on the imaginary line L connecting the central axis J and the radial inner edge 221 of the first blade 22 arranged on the other side in the circumferential direction C of the respective second blades 23. In addition, in the present embodiment, the radial outer end 237 at the radial inner edge 231 is a portion identical to an upper end 232 of the second blade 23.

A radial outer edge 233 of the second blade 23 extends upward as it extends radially outward. This enlarges the area of the second blade 23, thereby improving the blowing efficiency. That is, the blowing efficiency is improved because the area of the pressure surface of the second blade 23 becomes larger than that in a case where the radial outer edge 233 extends upward along a direction parallel to the central axis J, for example. As shown in FIG. 5, the radial outer edge 233 extends in the normal direction on the upper surface of the base portion 21.

As shown in FIGS. 4 and 5, when the second blade 23 is viewed from the radial outward, an upper edge 236 of the second blade 23 is a curved surface protruding to one side in the circumferential direction C. That is, when the second blade 23 is viewed from the radial outward, the upper edge 236 is curved so as to expand to one side in the circumferential direction C. This makes it possible to discharge gas radially outward and downward along the curved surface protruding to one side in the circumferential direction C in the second blade 23, thereby improving the blowing efficiency. Furthermore, unlike the first blade 22, the upper edge 236 of the second blade 23 is a curved surface protruding to one side in the circumferential direction C overall. In the present embodiment, the second blade 23 is shorter in longitudinal length than the first blade 22. However, because the upper edge 236 of the second blade is not formed with a curved surface protruding to the other side in the circumferential direction C, no unevenness is formed on the positive pressure surface side of the second blade 23, and it is hence possible to suppress the gas flowing to the positive pressure surface side of the second blade 23 from being separated from the positive pressure surface, and a vortex from being generated.

As shown in FIGS. 4 to 6, a radial outer end 234 of the second blade 23 is arranged on one side in the circumferential direction C relative to a middle 24 in the circumferential direction C of a radial outer end 224 at the first blade 22 adjacent in the circumferential direction C. This improves the blowing efficiency at the impeller 2. That is, in the impeller 2 of the present embodiment, the blowing efficiency is improved as compared with a case where the radial outer end 234 of the second blade 23 is arranged in the vicinity of the middle in the circumferential C of the radial outer end 224 of the first blade 22 adjacent in the circumferential direction C, for example. In the present embodiment, the length in the circumferential direction C between the radial outer end 234 of a certain second blade 23 and the radial outer end 224 of the first blade 22 adjacent to the other side in the circumferential direction C of the second blade 23 is about twice the length in the circumferential direction C between the radial outer end 234 of the second blade 23 and the radial outer end 224 of the first blade 22 adjacent to one side in the circumferential direction C of the second blade 23.

In the present embodiment, the radial outer ends 224 of the first blade 22 are arranged at equal intervals in the circumferential direction C. In addition, the radial outer ends 234 of the second blade 23 are also arranged at equal intervals in the circumferential direction C. This improves the rotational balance of the impeller 2. This allows the impeller 2 to accurately rotate about the central axis J even in a case where the impeller 2 rotates at a high speed.

As shown in FIG. 6, the first blade 22 is connected with the base portion 21 in a first connection region 25, and the second blade 23 is connected with the base portion 21 in a second connection region 26. In the present embodiment, the base portion 21 is a substantially conical portion. Therefore, the first connection region 25 and the second connection region 26 are boundaries between portions where the first blade 22 and the second blade 23 extend, with the upper surface of the base portion 21 forming a substantially conical surface as a reference.

In planar view, the curvatures of the first connection region 25 and the second connection region 26 are not constant. In addition, the curvature of the first connection region 25 is larger than the curvature of the second connection region 26. More specifically, in planar view, the minimum value of a radius R1 of curvature in the first connection region 25 of the base portion 21 and the surface of the other side in the circumferential direction C of the first blade 22 is smaller than the minimum value of a radius R2 of curvature in the second connection region 26 of the base portion 21 and the surface of the other side in the circumferential direction C of the second blade 23. This can suppress the gas flowing in the vicinity of the first connection region 25 and the second connection region 26 from being separated from the negative pressure surfaces of the first blade 22 and the second blade 23, thereby improving the blowing efficiency of the impeller 2.

As shown in FIG. 5, in the present embodiment, a lower end 225 of the first blade 22 and a lower end 235 of the second blade 23 have the same axial position. An axial length L2 of the second blade 23 is longer than half of an axial length L1 of the first blade 22. In other words, when the impeller 2 is viewed from the radial outward, the upper end 232 of the second blade 23 is arranged upward relative to an axial midpoint 27 between an upper end 222 of the first blade 22 and the lower end 225 of the first blade 22. Here, the axial length L1 of the first blade 22 is the length in the axial direction from the lower end 225 to the upper end 222 of the first blade 22. The axial length L2 of the second blade 23 is the length in the axial direction from the lower end 235 to the upper end 232 of the second blade 23. Due to this, the gas flowing in between the circumferential direction C of the first blades 22 adjacent in the circumferential direction C can be guided along the pressure surface or the negative pressure surface of the second blades 23 as upward as possible, thereby allowing generation of turbulence to be suppressed.

The present disclosure can be used in an impeller, for example. Furthermore, the impeller of the present disclosure can also be used in a blower or a vacuum cleaner. In addition, the present disclosure can be used in other electrical apparatuses.

Features of the above-described preferred embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.

While example embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims. 

What is claimed is:
 1. An impeller that is rotatable about a vertically extending central axis, the impeller comprising: a base portion extending radially outward as it extends downward; a plurality of first blades circumferentially arrayed on an upper surface of the base portion and extending on one side in a circumferential direction as it extends upward; and a plurality of second blades between a circumferential direction of the circumferentially adjacent first blades and extending on one side in a circumferential direction as it extends upward; wherein a radial outer end of the second blade is on one side in a circumferential direction relative to a middle in a circumferential direction of a radial outer end of the circumferentially adjacent first blade.
 2. The impeller according to claim 1, wherein a radial inner edge of the first blade extends upward as it extends radially outward.
 3. The impeller according to claim 1, wherein a radial outer edge of the first blade extends upward as it extends radially outward.
 4. The impeller according to claim 1, wherein when the first blade is viewed from a radial outward, an upper portion of an upper edge of the first blade is a curved surface protruding to another side in a circumferential direction, and a lower portion of the upper edge of the first blade is a curved surface protruding to the one side in the circumferential direction.
 5. The impeller according to claim 1, wherein a radial inner edge of the second blade extends upward as it extends radially outward.
 6. The impeller according to claim 1, wherein a radial outer edge of the second blade extends upward as it extends radially outward.
 7. The impeller according to claim 1, wherein in a planar view, the radial inner edge of the second blade is on the one side of the circumferential direction as it extends radially outward.
 8. The impeller according to claim 1, wherein when the second blade is viewed from a radial outward direction, an upper edge of the second blade is a curved surface protruding to the one side in the circumferential direction.
 9. The impeller according to claim 1, wherein in a planar view, a radial inner edge of the first blade extends along an imaginary line radiating from a central axis.
 10. The impeller according to claim 9, wherein in a planar view, a radial outer end at a radial inner edge of at least one of the second blades is on the imaginary line.
 11. The impeller according to claim 1, wherein when the impeller is viewed from a radial outward direction, an upper end of the second blade is located above an axial midpoint between an upper end of the first blade and a lower end of the first blade.
 12. The impeller according to claim 1, wherein in a planar view, a minimum value of a radius of curvature in a first connection region of the base portion and a surface of another side in a circumferential direction of the first blade is smaller than a minimum value of a radius of curvature in a second connection region of the base portion and a surface of another side in a circumferential direction of the second blade.
 13. The impeller according to claim 1, wherein radial outer ends of the first blade are located at equal intervals in a circumferential direction, and radial outer ends of the second blade are located at equal intervals in a circumferential direction.
 14. A blower, comprising the impeller according to claim
 1. 15. A vacuum cleaner, comprising the blower according to claim
 14. 